Cryogenic fluids are typically transported to a receiving station as either a compressed gas or a cryogenic liquid, depending on factors which include cryogenic fluid usage rate and whether the cooling capacity of the liquid cryogenic fluid is needed by the customer. If the cooling capacity of the liquid cryogenic fluid is needed, then a liquid supply is required. If no cooling capacity is needed by the customer, the cryogenic fluid can be delivered as either a liquid or compressed gas. Where there is a high cryogenic fluid consumption rate at a facility, it is preferable to deliver the fluid as a liquid, since a larger quantity of product can be stored for a given vessel volume. Conversely, if the facility's cryogenic fluid usage rate is low, delivering the fluid as a compressed gas is preferred due to the cost of liquefaction.
As illustrated in FIGS. 2A and 2B, cryogenic fluid suppliers typically employ one supply chain or distribution system for the transportation and delivery of a compressed gas and a separate or different supply chain or distribution system for the transportation and delivery of a cryogenic liquid. For example, hydrogen can be supplied to a customer as a liquid from a liquid trailer, or as a compressed gas from cylinders, tube trailers and, in some cases, through a pipeline. When tube trailers are used, hydrogen is often offloaded from the trailers by utilizing a pressure difference between the tubes on the trailer and the receiving tubes or vessels. Alternatively, the entire tube trailer may be dropped off or left behind and exchanged for a depleted or relatively empty tube trailer. Equipment has been designed to allow cryogenic fluids to be transported at high pressures, thereby maximizing the amount of fluid stored on, for example, a trailer. The sequencing or logistics of customer deliveries has also been tailored to minimize the amount of residual gas in tubes when a delivery vehicle returns to a fill station after completing deliveries.
FIGS. 3A and 3B illustrate that in known methods of delivering a cryogenic fluid as a compressed gas, either the delivery vehicle or receiving station must be configured to compress the cryogenic fluid to acceptable pressures (e.g., pressures in the range of around 100-700 bar).
U.S. Pat. No. 3,369,372 (“'372 Patent”) describes a liquid helium distribution system. U.S. Pat. No. 5,762,119 (“'119 Patent”) describes a cryogenic gas transportation and delivery system for transporting the gas in a liquefied state and delivering it to a storage vessel in a vaporized or gaseous state.
Known cryogenic fluid delivery methods suffer from numerous drawbacks. Having to use two different types of delivery vehicles in order to deliver cryogenic liquids and gases separately is inherently expensive and inefficient: the more delivery vehicles required, the greater the delivery expenses and odds of delivery disruption. Where the maximum allowable working pressure for storage equipment at a compressed gas facility is greater than a delivery vehicle's supply pressure, expensive compression equipment must be maintained at the facility to aid in compressed gas delivery. Also, separate compressed gas and cryogenic liquid supply chains cannot be modified readily to account for changes in the level or type of cryogenic fluid demand at any given cryogenic fluid receiving station.
Accordingly, the need exists for economical methods that enable efficient delivery of both compressed gases and cryogenic liquids to a number of cryogenic fluid receiving stations.